A cornerstone of the energy revolution

The bio-methane plant promoted by the German Renewable Energy Act (EEG) supplies around 60 buildings of a social facility via a local heating network. These include residential facilities for people with disabilities, along with associated workshops, a school, and other local heat consumers, with approximately 7 GWh of heat per year – a major location advantage for bio-methane CHP plants. Since they only require a gas connection, they can also be easily operated in densely populated areas. The required gas – bio-methane traded on the balance sheet – is sourced from the natural gas network. By using a buffer storage system, the plant can achieve lucrative additional revenues through demand-oriented electricity feed-in at the electricity exchange, as Philip Overwien, project developer at Wiehenenergie, reports: “We have commissioned Next Kraftwerke for the marketing of the electricity on the short-term markets. We provide our plant schedule via a portal, and the Next Kraftwerke team automatically knows to schedule the plant for trading. The process and collaboration work flawlessly for us."

In addition to providing local heat, the plant, like all other plants in the portfolio of Wiehenenergie, contributes to the stabilization of the German electricity grid by providing and supplying balancing energy via the virtual power plant of Next Kraftwerke. Similar to demand-oriented feed-in, the restrictions on heat supply obligations in this market segment are not as significant as often assumed. "All our plants have more or less large buffer storage facilities. These buffer storage systems allow us to handle longer balancing energy activations without any problems. We have already completed one-hour activations without any impact on heat supply," Overwien notes. "For very short activations, we don’t even need to rely on buffer storage, as heat is a relatively inert medium, and short-term fluctuations in electricity production do not directly affect heat production." The bio-methane plants of Wiehenenergie primarily offer their capacity in the negative secondary reserve (aFRR), but providing positive secondary reserve has also been considered in the past.

Whether it's about providing balancing energy or heat supply for public facilities, for Wiehenenergie, the versatile benefits of CHP plants are beyond question. However, new challenges have emerged recently concerning the procurement of bio-methane. "Especially in the last few years, the energy market has been highly volatile, and methane prices have also increased. This is one reason why we are currently considering new additional energy resources." As a result, Wiehenenergie has expanded its focus to include the construction and operation of PV systems. While the company remains committed to the heat sector with its CHP plants, it aims to diversify its portfolio to be more flexible in meeting future demands and, depending on the required electricity or heat concept, to be able to rely on other technologies.

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